Expansible mandrel



Feb. 3, 1970 FI'GI IBb 36 34 P. B. SEAY 3,493,189

EXPANS I BLE MANDREL Filed March 21!, 1968 PHILIP B. SEAY w/ma efmy ATTORNEYS United States Patent O 3,493,189 EXPANSIBLE MANDREL I Philip B. Seay, Richmond, Va., assignor to The Inta-Roto Machine Company, Inc., Richmond, Va., a corporation of Virginia Filed Mar. 21, 1968, Ser. No. 714,863 Int. Cl. B65h 75/24. I US). Cl. 242-72 1 Claim ABSTRACT OF THE DISCLOSURE An expansible mandrel in which a unitary shaft is provided with longitudinal grooves receiving inflatable tubes. The tubes normally reside flush with or below the surface of the shaft and are held in place by a combination of tube plug and saddle clamp. Certain of the tube plugs communicate the interiors of the tubes with a valve device by means of which the tubes may be inflated to expand against the interior of a core.

Background of the invention In the winding and rewinding of web material, as for example paper, the web is wound on a core having an inside diameter slightly larger than the shaft of the winding mechanism. In this way, the core readily may be slipped on and off the shaft. As a consequence, means must be provided to effect a driving connection between the shaft and the core and such means usually comprises mechanically actuated radially movable grippers. Such grippers and their actuating mechanism are subject to defective operation and increase weight while weakening the shaft.

' In an effort to improve upon the mechanically expansible mandrels it has been proposed, see Patent No. 2,062,- 421, to provide a generally cylindrical mandrel with a plurality of longitudinally disposed edged fins extending radially from the periphery thereof and expansible tubes disposed between and upon opposite sides of said fins. After a core is positioned on said mandrel in surrounding relation thereto, the tubes are inflated to distort the core by flattening the areas between said tubes to cause the fins to become inbedded in said core areas. Thus, the mandrel must be somewhat smaller than the core to accommodate insertion of the fins, thereby weakening the mandrel, and the core is undesirably distorted.

Summary of the invention An expansible mandrel according to the present invention has a substantial degree of rigidity and strength since the web material may be of substantial weight. The shaft is essentially solid with only a limited number of shallow trapezoidal sectional grooves equispaced around the circumference and extending longitudinally of the shaft. Expansible tubes of trapezoidal section are nested in said grooves and in relaxed condition lie within the circumference of the shaft. Thus, with no projections beyond its surface, the shaft may be made to conform very closely to the inner diameter of the cores with which it is to be used so that the expansible drive means cannot materially deform the core. In paper web winding, the cores are made normally of cardboard and the use of internally expanding gripper means tends to deform these cores. In the present case, the shaft so closely approximates the inner diameter of the core that very little distortion is possible.

Brief description of the drawings FIG. 1 is a plan view of a mandrel according to the present invention;

3,493,189 Patented Feb. 3, 1970 FIG. 2 is an enlarged longitudinal cross sectional view taken axially through the mandrel of FIG. 1 and on the plane of line 2-2 of FIG. 3;

FIG. 3 is an enlarged transverse cross sectional view taken on the plane of line 33 in FIG. 2;

FIG. 4 is an enlarged transverse cross sectional view taken on the plane of line 44 in FIG. 2, and

FIG. 5 is an enlarged, exploded perspective view showing an end portion of one of the inflatable tubes, the plug and the saddle clamp associated therewith.

Detailed description of invention Referring now to the drawing in detail, specifically to FIG. 1, a mandrel 10, in accordance with the present invention comprises a cylindrical main body portion 12, and axially spaced bearing portions 14 by means of which the mandrel is rotatably supported on a web winding machine, not shown. A drive coupling member 16 is connected to one end of the mandrel so that winding or rewinding rotation may be imparted to the mandrel, the power source not being shown. The mandrel 10 also includes a plurality of expansible internal gripping members 18 extending longitudinally of the body portion 12. At least one bearing portion 14, preferably the bearing at the idler end of the mandrel, has a diameter not greater than that of the mandrel body portion 12 to permit the passage of a hollow cylindrical core thereover.

The mandrel body portion 12 preferably is solid to provide rigidity and strength, and is provided with a plurality of longitudinally or axially extending grooves or channels 22 opening through the periphery 24 of the body and equidistantly, preferably three in number, spaced circumferentially therearound. The expansible gripping members 18 comprise hollow tubes of rubber or similar expansible or elastic material, having hollow interiors 26, and they are nested in the channels 22. I

As shown in FIG. 3 the outer surface 24 of the mandrel body 12 conforms loosely to the inner surface c of the core c, a part only of which is shown. The gripping members 18 each are of generally trapezoidal cross section. Preferably, the major inner surface 28 of each tube is flat while the minor outer surface 30 is arcuate, the side surfaces 32 also being flat. The channels 22 are trapezoidal to complement the tube surfaces or sides 28 and 32, and snugly receive the tubes there-within.

It is also preferred that the arcuate minor surfaces or sides 30 be situated to lie slightly less than flush with the mandrel peripheral surface 24 when the gripping members 18 are relaxed in non-expanded condition, as illustrated by the lower tubes in FIG 3. In this way, the surface 24 may be made, as described above, to conform generally to the inner surface 0, of the core c. Then, when the gripping members 18 are expanded by the application of fluid pressure to their hollow interiors 26, the engagement of the minor sides 30 against the inner core surface 0' cannot appreciably deform the core 0, as illustrated by the expanded upper tube 18 in FIG. 3.

The opposite end portions 18a, 18b, of the tubes 18 are sealed so that elevated fluid pressure will expand the tubes and establish gripping action with the core 0, and the tubes also are clamped to the mandrel body at said end portions to augment the dove-tail like fit between the tubes 18 and channels 22. Plug members 34 are inserted into the tube ends and the latter are secured by saddle clamps 36. Each plug includes a body 38 preferably provided with a pair of spaced, circumferentially extending sealing ribs 40 which bear with locally augmented pressure against, and are embedded in, the interior walls of the tubes, as shown in FIG. 2.

At least those plugs used in the tube ends 18a at the right hand side in FIG. 2, and for uniformity of manufacture, preferably all of the plugs, are provided with a bore 42 leading inwardly from one face 44 to a point of intersection with a further bore 46 from the underside 48 of the plug. The opening of the bore 46 preferably is surrounded by an annular sealing rib 50. The major side 28 at one end of each tube 18 is provided with an opening 52 with which the opening of the plug bore 46 is aligned.

The shaft 12, at the end corresponding to the tube ends 18a is provided with a relatively small axially disposed bore 54 which is in communication at its inner end with radially disposed bores 56 respectively opening through the floor of the respective channels 22. When assembled as shown in FIG. 2, the plug bore 46, the tube opening 52 and the respective radial bore 56 in the shaft are registered. The axial bore 54 in the shaft 12 leads to the adjacent end thereof whereat a suitable valve 58 is located to allow application of fluid under pressure to the interior 26 of the gripping members 18. As shown in FIG. 2, the plugs 34 at the opposite ends 18b of the tubes 18 may be oriented so that the bores 42 do not communicate with the tube interiors.

Each plug and its corresponding end portion of the tube members 18 are firmly gripped and held in place by the respective saddle clamps 36. The shaft 12 is provided with flats 60, as shown in FIG. 4, coplanar with the floors of the respective channels 22 and providing seats for the clamps, and fasteners 62 hold the clamps in place. It will be noted that the arcuate outer surfaces 64 of the clamps conform to the outer surface 24 of the shaft so as not to interfere with the reception or removal of a core. For this reason also, of course, the heads of the fasteners 62 are received in counterbores 66 in the end portions 68 of the clamps.

Since the depths of the flats must be greater than the depths of the channels or grooves 22 by an amount equal to the radial dimension of the bridge portion 70 of each saddle clamp which joins its foot portions 68, inclined continuations 22' are provided at the opposite ends of each groove 22 in order to allow smooth intersections with the flats 60, see particularly FIG. 2.

In use, the core is simply slipped onto the shaft and a suitable source of fluid under pressure (such as an air hose) is applied to the exposed nipple of the valve 58. This pressure expands the members 18 into gripping contact with the interior 0' of the core. The gripping action is held by the one-way action of the valve 58, and is released when desired by manipulation of the valve. In this respect, it will be appreciated that the valve 58 is in a form identical with or similar to those valves conventionally used for admitting air under pressure to an automotive tire.

It will be noted that the body portion 12 of the mandrel 10 is solid throughout with the exception of the grooves or channels 22 and the fluid passage bore 54, but these areas are so minor, compared to the body 12 as a Whole, that they are immaterial and do not weaken the mandrel' to any appreciable extent. As an example, the dimensions of one mandrel that has proven highly successful comprises a mandrel approximately 54 inches long between the bearings 14 for use with a core approximately 46 inches long so that the bore 54 does not even extend into the core supporting portion. The diameter of the mandrel is approximately 3 inches and the depth of the grooves 22 about one half inch, the inner base walls being about 1 /8 inches and the spacing between the corners of the periphery 24 and the side groove walls being about 1 inch. Thus, for all practical purposes, the body 12 is substantially solid and has great strength.

What is claimed is: 1. An expandible mandrel comprising, in combination: an elongate shaft having a main body portion adapted to fit within a deformable core and being of a diameter closely approximating the inner diameter of such core, said main body portion having a plurality of longitudinally extending grooves, each groove being of trapezoidal shape in cross section with the opposite sides of each groove diverging inwardly from the surface of said main body portion,

an elongate hollow tube received in each groove, each tube being of trapezoidal shape in cross section and dimensioned similarly to the grooves so as to be keyed therewithin, and each tube having an outer surface portion lying slightly below the surface of said main body portion, when relaxed, and adapted to expand therebeyond to contact and grippingly engage the core when inflated without unduly distorting the core,

means for anchoring the opposite ends of said tubes to said shaft,

and passage means for introducing fluid under pressure to the interior of each tube.

References Cited UNITED STATES PATENTS 2,145,806 l/ 1939 Schnedarek. 3,214,109 10/ 1965 Gadde et a1. 3,273,817 9/1966 Damiron. 2,062,421 12/1936 Lindbom. 2,289,453 7/ 1942 Randall. 3,223,341 12/1965 Gadde.

NATHAN L. MINTZ, Primary Examiner 

